Lombardo for sentimental reasons. Along with Nicko McBrain, he was the reason I became a drummer 110 years ago.
Mastadon's drummer (I forget the name) is awesome. Tricky rhythms and bone-shaking sound for such a comparatively rock-oriented metal act.
Shame that Kevin Talley from Fetus is no longer playing metal. Phenomenal talent.
I love Dream Theater, but Portnoy is just too consistently showy for my tastes. I think he's all too aware of how great he is.
Longstreth from Origin is amazing, but (like Raymond Herrera) is also triggered to hell live, which annoys me for some reason.
My $.02.